Motion damping apparatus

Claim 2

A control system for a stepping motor having a movable member and a plurality of phase windings comprising, in combination: means for providing signals sequentially to said windings for creating torque to move said movable member; means coupled to said movable member for producing a first signal when said movable member is in motion and a second different signal when it is stopped; and means responsive to an indication that said movable member is approaching its final step and to said first signal indicating said movable member is in motion for removing a signal from the phase winding which produces maximum torque to move said movable member to its final step and for applying a signal to a different phase winding to produce a reverse torque on said movable member only when said first signal is present whereby said movable member is stopped.

Claim 3

The combination as set forth in claim 1 further including means responsive to said second signal for causing a signal to be removed from said different phase winding and reapplied to tHe phase winding which produces maximum torque to move said movable member to its final step.

Claim 4

The combination as set forth in claim 1 wherein said means coupled to said movable member comprises a means for producing an electrical signal proportional to the speed of said movable member and having a unique value when said movable member is motionless and means coupled thereto for producing a first substantially constant signal when said means for producing electrical signals produces a signal other than at said unique value and for producing a second different signal when said means is producing said unique signal.

Claim 5

The combination as set forth in claim 1 wherein said movable member is movable in each of two directions and wherein said member coupled thereto produces a first signal when said movable member is moving in one direction and a second signal when said movable member is moving in the other direction and wherein the means responsive to an indication that said movable member is approaching its final step is responsive to one of said first and second signals for applying signals to a phase winding to provide reverse torque in the proper direction.

Claim 6

A control system for a stepping motor having a rotatable shaft and a plurality of phase windings for controlling the position thereof comprising, in combination: means responsive to a signal indicating the number of steps said shaft is to be moved for applying signals sequentially to said phase windings for applying torque for rotating said shaft; tachometer means coupled to said shaft for producing a signal of a polarity indicative of the direction of shaft movement and of an amplitude proportional to the speed of said shaft; means responsive to the signal from said tachometer for producing a first substantially constant signal when said shaft is moving in one direction and a second substantially constant signal when said shaft is moving in the opposite direction; and means responsive to a signal indicating a phase winding is being energized for moving said shaft to its final step and to one of said first and second substantially constant signals for de-energizing said energized phase winding and for energizing a different phase winding to produce backtorque to stop the motion of said shaft.

Claim 7

A control system for a stepping motor having a rotatable shaft and a plurality of phase windings for controlling the position thereof comprising, in combination: means responsive to a signal indicating the number of steps said shaft is to be moved for applying signals sequentially to said phase windings for applying torque for rotating said shaft; tachometer means coupled to said shaft for producing a signal of a polarity indicative of the direction of shaft movement and of an amplitude proportional to the speed of said shaft; means responsive to the signal from said tachometer for producing a first substantially constant signal when said shaft is moving in one direction and a second substantially constant signal when said shaft is moving in the opposite direction; and means responsive to a signal indicating a phase winding is being energized for moving said shaft to its final step and to one of said first and second substantially constant signals for de-energizing said energized phase winding and for energizing a different phase winding to produce backtorque to stop the motion of said shaft.

Claim 8

The combination as set forth in claim 5 wherein said means responsive to said tachometer signals produces a third signal when said shaft ceases motion for removing said backtorque signal.

Claim 9

The combination as set forth in claim 6 further including means also responsive to said third signal for reapplying a signal to the winding which moves said shaft to said final step.